The present invention relates to an armor piercing shell of the kind comprising a nose cone with a reinforced tip for mechanical penetration of active armor and an impact contact member placed in the nose cone of the shell arranged to provide initiation of the charge upon impact of the shell against a target.
For combating armoured vehicles, particularly tanks, it is previously known to use different types of antitank ammunition. Such ammunition is designed to penetrate even thick armor plates. Armor piercing shells are a special type of anti-tank ammunition which is provided with a hollow charge warhead. In principle, a hollow charge warhead comprises an outer casing, a metal cone and an explosive. when the explosive detonates, the metal cone is squeezed together and a metal jet is formed which, with great force, penetrates even very thick and hard armor. By virtue of its good effect in armored targets, the hollow charges have long constituted a serious threat to armoured vehicles.
Due to the development that has taken place on the protection side through the introduction of composite armor, active armor, etc, the importance of improving the penetrability of the warhead has, however, increased.
Armored targets can be equipped with active armor in the form of separate mountings placed in front of and at a distance from the main armor of the target. Such active armor may typically comprise two steel plates with an intermediate layer of pentyl explosive paste. Normally, active armor of this kind will disturb the hollow charge jet of the shell, its penetrative ability being drastically reduced due to the fact that the jet is broken up into fragments which tumble and are dispersed.
An armor piercing shell with provided penetrative ability against active armor is previously known by EP No. 0 196 283. In this case the improved penetrative ability has been accomplished by means of a specific design of the nose cone of the shell so that it is able to mechanically pentrate the active armor before the hollow charge is initiated. This means that the penetration jet of the hollow charge can pass undisturbed by the active armor so that full penetrability is obtained in the main target. Specifically, the nose cone has a reinforced tip for mechanical penetration of the active armor and the impact contact member is so positioned in the nose cone that contact is obtained only when the reinforced tip has penetrated aside the active armour without detonation.
In this European patent publication a preferred embodiment is illustrated in which the tip of the nose cone is solid and sharper than in conventional anti-tank shells and the impact contact member is not extended all the way to the tip of the shell. By this means, the delay is accomplished which is required in order for the shell to have time to penetrate the active armour before the hollow charge is initiated.
Armor piercing shells of the above-mentioned type have a very good effect at typical angles of impact, that is angles within the range of 20.degree.-60.degree.. At very small angles of impact, such as 20.degree.-30.degree.. there is a tendency, however, that the shell case is twisted at the impact with a deteriorated contact function as a consequence.
Also on impacts perpendicular to the armor there is a tendency to a deteriorated contact function for the above-mentioned armor piercing shell which might depend on a certain bending of the walls of the nose cone on impact with an undesired delay of the contact function as a result.